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Computer simulation has become established in a two-fold way: As a tool for planning, analyzing, and optimizing complex systems but also as a method for the scientific instigation of theories and thus for the generation of knowledge. Generated results often serve as a basis for investment decisions, e.g., road construction and factory planning, or provide evidence for scientific theory-building processes. To ensure the generation of credible and reproducible results, it is indispensable to conduct systematic and methodologically sound simulation studies. A variety of procedure models exist that structure and predetermine the process of a study. As a result, experimenters are often required to repetitively but thoroughly carry out a large number of experiments. Moreover, the process is not sufficiently specified and many important design decisions still have to be made by the experimenter, which might result in an unintentional bias of the results.
To facilitate the conducting of simulation studies and to improve both replicability and reproducibility of the generated results, this thesis proposes a procedure model for carrying out Hypothesis-Driven Simulation Studies, an approach that assists the experimenter during the design, execution, and analysis of simulation experiments. In contrast to existing approaches, a formally specified hypothesis becomes the key element of the study so that each step of the study can be adapted and executed to directly contribute to the verification of the hypothesis. To this end, the FITS language is presented, which enables the specification of hypotheses as assumptions regarding the influence specific input values have on the observable behavior of the model. The proposed procedure model systematically designs relevant simulation experiments, runs, and iterations that must be executed to provide evidence for the verification of the hypothesis. Generated outputs are then aggregated for each defined performance measure to allow for the application of statistical hypothesis testing approaches. Hence, the proposed assistance only requires the experimenter to provide an executable simulation model and a corresponding hypothesis to conduct a sound simulation study. With respect to the implementation of the proposed assistance system, this thesis presents an abstract architecture and provides formal specifications of all required services.
To evaluate the concept of Hypothesis-Driven Simulation Studies, two case studies are presented from the manufacturing domain. The introduced approach is applied to a NetLogo simulation model of a four-tiered supply chain. Two scenarios as well as corresponding assumptions about the model behavior are presented to investigate conditions for the occurrence of the bullwhip effect. Starting from the formal specification of the hypothesis, each step of a Hypothesis-Driven Simulation Study is presented in detail, with specific design decisions outlined, and generated inter- mediate data as well as final results illustrated. With respect to the comparability of the results, a conventional simulation study is conducted which serves as reference data. The approach that is proposed in this thesis is beneficial for both practitioners and scientists. The presented assistance system allows for a more effortless and simplified execution of simulation experiments while the efficient generation of credible results is ensured.
Rückkehrprozesse aus Genderperspektive: remigrierte (Spät-)Aussiedler-Ehepaare in Westsibirien
(2019)
Die Studie untersucht die Rückkehrprozesse von (Spät-)Aussiedler-Ehepaaren aus Deutschland nach Westsibirien. Ein besonderes Augenmerk wird auf die Sichtweisen der Frauen und Männer hinsichtlich ihrer gemachten Erfahrung der Remigration gelegt. Darüber hinaus analysiert die Studie einerseits die Gemeinsamkeiten und Unterschiede beider Geschlechter im Hinblick auf die Rückkehrmotive, die Zufriedenheit mit der Wiederanpassung in Russland sowie die Einstellung hinsichtlich einer erneuten Migration nach Deutschland. Andererseits fokussiert die Arbeit auf die Geschlechterverhältnisse unter den Ehegatten im Prozess der Entscheidungsfindung zur Remigration. Die Studie folgt einem qualitativen methodischen Ansatz und verbindet verschiedene Forschungsrichtungen, genauer (Re)Migrations-, Familien-, (Spät-)AussiedlerInnen- und Geschlechterforschung.
Our goal is to approximate energy forms on suitable fractals by discrete graph energies and certain metric measure spaces, using the notion of quasi-unitary equivalence. Quasi-unitary equivalence generalises the two concepts of unitary equivalence and norm resolvent convergence to the case of operators and energy forms defined in varying Hilbert spaces.
More precisely, we prove that the canonical sequence of discrete graph energies (associated with the fractal energy form) converges to the energy form (induced by a resistance form) on a finitely ramified fractal in the sense of quasi-unitary equivalence. Moreover, we allow a perturbation by magnetic potentials and we specify the corresponding errors.
This aforementioned approach is an approximation of the fractal from within (by an increasing sequence of finitely many points). The natural step that follows this realisation is the question whether one can also approximate fractals from outside, i.e., by a suitable sequence of shrinking supersets. We partly answer this question by restricting ourselves to a very specific structure of the approximating sets, namely so-called graph-like manifolds that respect the structure of the fractals resp. the underlying discrete graphs. Again, we show that the canonical (properly rescaled) energy forms on such a sequence of graph-like manifolds converge to the fractal energy form (in the sense of quasi-unitary equivalence).
From the quasi-unitary equivalence of energy forms, we conclude the convergence of the associated linear operators, convergence of the spectra and convergence of functions of the operators – thus essentially the same as in the case of the usual norm resolvent convergence.
Heimatfabrik Lokalmuseum bietet einen neuen Blick auf lokal verankerte Museen. Anhand von ausgewählten Fallbeispielen, die durch eine quantitative Untersuchung von etwa 370 Museen im Großherzogtum Luxemburg und in der belgischen Region Wallonien ergänzt werden, analysiert die Autorin, welche Identifikationsangebote bäuerliche Alltagsmuseen, Stadtmuseen, Industriemuseen, Kriegsmuseen und Auswanderermuseen ihren Besuchern bieten. Wen schließen die Museumsverantwortlichen durch ihre Erzählweisen ein und wen grenzen sie aus? Wie gehen sie mit sprachlichen, konfessionellen, kulturellen, sexuellen und soziale Minderheiten um?
Das Buch beginnt mit der Klärung der Frage, wie sich das Heimatverständnis in Luxemburg in Luxemburg und im angrenzenden Wallonien im Spannungsfeld zwischen dem klassischen Heimatbegriff des deutschsprachigen Raums und der Inwertsetzung der Landschaft durch die französischen Humangeographen seit der Mitte des 19. Jahrhunderts entwickelt hat. Aus diesem unterschiedlichen Zugang zu dem was als enger Kreis des gesellschaftlichen Zusammenhalts empfunden wird, ergeben sich verschiedene Typen von lokalhistorischen Museen, die die Autorin in historischer Perspektive vorstellt.
Indem sie Dinge des Alltags durch die Aufnahme in ihre Sammlungen zu symbolischen Zeichenträgern einer Gesellschaft erheben sind Museen privilegierte Orte für die Schaffung von Heritage. Mit den Ausstellungen erzeugen die Museumsträger eine subjektiv empfundene gesellschaftliche Einheit, die von manchen Besucher als Heimat angenommen oder abgelehnt wird, andere wiederum gleichgültig lässt. Vor diesem Hintergrund dieser Feststellung beschäftigt sich die Autorin mit dem, was unter lokalem heritage zu verstehen ist und welcher gestalterischen Mittel sich die Verantwortlichen von lokalhistorischen Museen bedienen um ihre Vorstellung von Heimat zu konstruieren. Anhand der Themenbereiche bäuerlicher Alltag, Natur, Ein- und Auswanderung, Krieg sowie Industrie geht das Buch der Frage nach, wie interne und externe Museumsstakeholder das vom Museum vermittelte Heimatbild und damit verbunden auch die nationale Geschichtskultur mitbestimmen.
Das Buch möchte dazu beitragen, den Blick einer interessierten Öffentlichkeit für lokales Kulturerbe zu schulen sowie Historiker auf das Potenzial von lokalhistorischen Museen hinzuweisen. In diesem Sinne ist die Untersuchung auch ein Plädoyer für die Anerkennung der Besonderheit von außerakademischer historischer Aufarbeitung und für die Verstärkung der Zusammenarbeit zwischen universitärer und außeruniversitärer Forschung.
In der Vorrede zur ersten Auflage von Die Welt als Wille und Vorstellung legt Arthur Schopenhauer dem Leser seines Werkes seine Absicht nahe, welche in der Mitteilung eines „einzigen Gedankens“ besteht. Doch dieser mitzuteilende Gedanke wird an keiner Stelle des Werkes explizit und direkt als solchen von Schopenhauer ausgesprochen und genannt. Dies gibt bis heute in der Schopenhauer-Forschung Anlass zu kontroversen Auseinandersetzungen: Wie lautet Schopenhauers „einziger Gedanke“? Wo befindet er sich konkret? Und ist er überhaupt mitteilbar?
Trotz zahlreicher Forschungsarbeiten zur Thematik des „einzigen Gedankens“ wurde bisher der Einfluss der indischen Philosophie, genauer des Oupnek’hat, vernachlässigt, obwohl genauestens nachgewiesen und nachgezeichnet werden kann, mit welchen Quellen sich Schopenhauer zum Zeitpunkt der Entstehung seiner Philosophie intensiv beschäftigt hat. Auch verweist er selbst immer wieder auf bestimmte Stellen aus dem Oupnek’hat und zitiert Passagen an ganz wesentlichen Stellen in seinem Werk.
Um den „einzigen Gedanken“ im Werk Schopenhauers erfassen zu können, reicht es nicht aus, nur vom Hauptwerk selbst auszugehen, sondern es müssen ebenfalls die Jahre und Schriften während der Entstehung seiner Philosophie bis zum Hauptwerk berücksichtigt werden, und damit verbunden auch die Quellen, die Schopenhauer beeinflusst haben, wozu insbesondere das Oupnek’hat samt seinen eigenen Randnotizen gehört.
This thesis sheds light on the heterogeneous hedging behavior of airlines. The focus lies on financial hedging, operational hedging and selective hedging. The unbalanced panel data set includes 74 airlines from 39 countries. The period of analysis is 2005 until 2014, resulting in 621 firm years. The random effects probit and fixed effects OLS models provide strong evidence of a convex relation between derivative usage and a firm’s leverage, opposing the existing financial distress theory. Airlines with lower leverage had higher hedge ratios. In addition, the results show that airlines with interest rate and currency derivatives were more likely to engage in fuel price hedging. Moreover, the study results support the argument that operational hedging is a complement to financial hedging. Airlines with more heterogeneous fleet structures exhibited higher hedge ratios.
Also, airlines which were members of a strategic alliance were more likely to be hedging airlines. As alliance airlines are rather financially sound airlines, the positive relation between alliance membership and hedging reflects the negative results on the leverage
ratio. Lastly, the study presents determinants of an airlines’ selective hedging behavior. Airlines with prior-period derivative losses, recognized in income, changed their hedge portfolios more frequently. Moreover, the sample airlines acted in accordance with herd behavior theory. Changes in the regional hedge portfolios influenced the hedge portfolio of the individual airline in the same direction.
The World's second oldest system of judicial review of national legislation emerged through court practice from the very first years after the adoption of the Constitution of Norway in 1814. The review is exercised by the ordinary courts at all levels with the single Supreme Court as the last instance. No specialized constitutional court has been established. The independence of the judiciary is generally recognized as high. But what degree of legitimacy should judges appointed in order to ensure ordinary judicial business enjoy when exercising a basically political function like reviewing and possibly setting aside acts of Parliament?
Systemische Resilienz
(2019)
Entrepreneurial ventures are associated with economic growth, job creation, and innovation. Most entrepreneurial ventures need external funding to succeed. However, they often find it difficult to access traditional forms of financing, such as bank loans. To overcome this hurdle and to provide entrepreneurial ventures with badly-needed external capital, many types of entrepreneurial finance have emerged over the past decades and continue to emerge today. Inspired by these dynamics, this postdoctoral thesis contains five empirical studies that address novel questions regarding established (e.g., venture capital, business angels) and new types of entrepreneurial finance (i.e., initial coin offerings).
With two-thirds to three-quarters of all companies, family firms are the most common firm type worldwide and employ around 60 percent of all employees, making them of considerable importance for almost all economies. Despite this high practical relevance, academic research took notice of family firms as intriguing research subjects comparatively late. However, the field of family business research has grown eminently over the past two decades and has established itself as a mature research field with a broad thematic scope. In addition to questions relating to corporate governance, family firm succession and the consideration of entrepreneurial families themselves, researchers mainly focused on the impact of family involvement in firms on their financial performance and firm strategy. This dissertation examines the financial performance and capital structure of family firms in various meta-analytical studies. Meta-analysis is a suitable method for summarizing existing empirical findings of a research field as well as identifying relevant moderators of a relationship of interest.
First, the dissertation examines the question whether family firms show better financial performance than non-family firms. A replication and extension of the study by O’Boyle et al. (2012) based on 1,095 primary studies reveals a slightly better performance of family firms compared to non-family firms. Investigating the moderating impact of methodological choices in primary studies, the results show that outperformance holds mainly for large and publicly listed firms and with regard to accounting-based performance measures. Concerning country culture, family firms show better performance in individualistic countries and countries with a low power distance.
Furthermore, this dissertation investigates the sensitivity of family firm performance with regard to business cycle fluctuations. Family firms show a pro-cyclical performance pattern, i.e. their relative financial performance compared to non-family firms is better in economically good times. This effect is particularly pronounced in Anglo-American countries and emerging markets.
In the next step, a meta-analytic structural equation model (MASEM) is used to examine the market valuation of public family firms. In this model, profitability and firm strategic choices are used as mediators. On the one hand, family firm status itself does not have an impact on firms‘ market value. On the other hand, this study finds a positive indirect effect via higher profitability levels and a negative indirect effect via lower R&D intensity. A split consideration of family ownership and management shows that these two effects are mainly driven by family ownership, while family management results in less diversification and internationalization.
Finally, the dissertation examines the capital structure of public family firms. Univariate meta-analyses indicate on average lower leverage ratios in family firms compared to non-family firms. However, there is significant heterogeneity in mean effect sizes across the 45 countries included in the study. The results of a meta-regression reveal that family firms use leverage strategically to secure their controlling position in the firm. While strong creditor protection leads to lower leverage ratios in family firms, strong shareholder protection has the opposite effect.
Die vorgelegte Dissertation trägt den Titel Regularization Methods for Statistical Modelling in Small Area Estimation. In ihr wird die Verwendung regularisierter Regressionstechniken zur geographisch oder kontextuell hochauflösenden Schätzung aggregatspezifischer Kennzahlen auf Basis kleiner Stichproben studiert. Letzteres wird in der Fachliteratur häufig unter dem Begriff Small Area Estimation betrachtet. Der Kern der Arbeit besteht darin die Effekte von regularisierter Parameterschätzung in Regressionsmodellen, welche gängiger Weise für Small Area Estimation verwendet werden, zu analysieren. Dabei erfolgt die Analyse primär auf theoretischer Ebene, indem die statistischen Eigenschaften dieser Schätzverfahren mathematisch charakterisiert und bewiesen werden. Darüber hinaus werden die Ergebnisse durch numerische Simulationen veranschaulicht, und vor dem Hintergrund empirischer Anwendungen kritisch verortet. Die Dissertation ist in drei Bereiche gegliedert. Jeder Bereich behandelt ein individuelles methodisches Problem im Kontext von Small Area Estimation, welches durch die Verwendung regularisierter Schätzverfahren gelöst werden kann. Im Folgenden wird jedes Problem kurz vorgestellt und im Zuge dessen der Nutzen von Regularisierung erläutert.
Das erste Problem ist Small Area Estimation in der Gegenwart unbeobachteter Messfehler. In Regressionsmodellen werden typischerweise endogene Variablen auf Basis statistisch verwandter exogener Variablen beschrieben. Für eine solche Beschreibung wird ein funktionaler Zusammenhang zwischen den Variablen postuliert, welcher durch ein Set von Modellparametern charakterisiert ist. Dieses Set muss auf Basis von beobachteten Realisationen der jeweiligen Variablen geschätzt werden. Sind die Beobachtungen jedoch durch Messfehler verfälscht, dann liefert der Schätzprozess verzerrte Ergebnisse. Wird anschließend Small Area Estimation betrieben, so sind die geschätzten Kennzahlen nicht verlässlich. In der Fachliteratur existieren hierfür methodische Anpassungen, welche in der Regel aber restriktive Annahmen hinsichtlich der Messfehlerverteilung benötigen. Im Rahmen der Dissertation wird bewiesen, dass Regularisierung in diesem Kontext einer gegen Messfehler robusten Schätzung entspricht - und zwar ungeachtet der Messfehlerverteilung. Diese Äquivalenz wird anschließend verwendet, um robuste Varianten bekannter Small Area Modelle herzuleiten. Für jedes Modell wird ein Algorithmus zur robusten Parameterschätzung konstruiert. Darüber hinaus wird ein neuer Ansatz entwickelt, welcher die Unsicherheit von Small Area Schätzwerten in der Gegenwart unbeobachteter Messfehler quantifiziert. Es wird zusätzlich gezeigt, dass diese Form der robusten Schätzung die wünschenswerte Eigenschaft der statistischen Konsistenz aufweist.
Das zweite Problem ist Small Area Estimation anhand von Datensätzen, welche Hilfsvariablen mit unterschiedlicher Auflösung enthalten. Regressionsmodelle für Small Area Estimation werden normalerweise entweder für personenbezogene Beobachtungen (Unit-Level), oder für aggregatsbezogene Beobachtungen (Area-Level) spezifiziert. Doch vor dem Hintergrund der stetig wachsenden Datenverfügbarkeit gibt es immer häufiger Situationen, in welchen Daten auf beiden Ebenen vorliegen. Dies beinhaltet ein großes Potenzial für Small Area Estimation, da somit neue Multi-Level Modelle mit großem Erklärungsgehalt konstruiert werden können. Allerdings ist die Verbindung der Ebenen aus methodischer Sicht kompliziert. Zentrale Schritte des Inferenzschlusses, wie etwa Variablenselektion und Parameterschätzung, müssen auf beiden Levels gleichzeitig durchgeführt werden. Hierfür existieren in der Fachliteratur kaum allgemein anwendbare Methoden. In der Dissertation wird gezeigt, dass die Verwendung ebenenspezifischer Regularisierungsterme in der Modellierung diese Probleme löst. Es wird ein neuer Algorithmus für stochastischen Gradientenabstieg zur Parameterschätzung entwickelt, welcher die Informationen von allen Ebenen effizient unter adaptiver Regularisierung nutzt. Darüber hinaus werden parametrische Verfahren zur Abschätzung der Unsicherheit für Schätzwerte vorgestellt, welche durch dieses Verfahren erzeugt wurden. Daran anknüpfend wird bewiesen, dass der entwickelte Ansatz bei adäquatem Regularisierungsterm sowohl in der Schätzung als auch in der Variablenselektion konsistent ist.
Das dritte Problem ist Small Area Estimation von Anteilswerten unter starken verteilungsbezogenen Abhängigkeiten innerhalb der Kovariaten. Solche Abhängigkeiten liegen vor, wenn eine exogene Variable durch eine lineare Transformation einer anderen exogenen Variablen darstellbar ist (Multikollinearität). In der Fachliteratur werden hierunter aber auch Situationen verstanden, in welchen mehrere Kovariate stark korreliert sind (Quasi-Multikollinearität). Wird auf einer solchen Datenbasis ein Regressionsmodell spezifiziert, dann können die individuellen Beiträge der exogenen Variablen zur funktionalen Beschreibung der endogenen Variablen nicht identifiziert werden. Die Parameterschätzung ist demnach mit großer Unsicherheit verbunden und resultierende Small Area Schätzwerte sind ungenau. Der Effekt ist besonders stark, wenn die zu modellierende Größe nicht-linear ist, wie etwa ein Anteilswert. Dies rührt daher, dass die zugrundeliegende Likelihood-Funktion nicht mehr geschlossen darstellbar ist und approximiert werden muss. Im Rahmen der Dissertation wird gezeigt, dass die Verwendung einer L2-Regularisierung den Schätzprozess in diesem Kontext signifikant stabilisiert. Am Beispiel von zwei nicht-linearen Small Area Modellen wird ein neuer Algorithmus entwickelt, welche den bereits bekannten Quasi-Likelihood Ansatz (basierend auf der Laplace-Approximation) durch Regularisierung erweitert und verbessert. Zusätzlich werden parametrische Verfahren zur Unsicherheitsmessung für auf diese Weise erhaltene Schätzwerte beschrieben.
Vor dem Hintergrund der theoretischen und numerischen Ergebnisse wird in der Dissertation demonstriert, dass Regularisierungsmethoden eine wertvolle Ergänzung der Fachliteratur für Small Area Estimation darstellen. Die hier entwickelten Verfahren sind robust und vielseitig einsetzbar, was sie zu hilfreichen Werkzeugen der empirischen Datenanalyse macht.
Hypothalamic-pituitary-adrenal (HPA) axis-related genetic variants influence the stress response
(2019)
The physiological stress system includes the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic-adrenal-medullary system (SAM). Parameters representing these systems such as cortisol, blood pressure or heart rate define the physiological reaction in response to a stressor. The main objective of the studies described in this thesis was to understand the role of the HPA-related genetic factors in these two systems. Genetic factors represent one of the components causing individual variations in physiological stress parameters. Five genes involved in the functioning of the HPA axis regarding stress responses are examined in this thesis. They are: corticotropin-releasing hormone (CRH), the glucocorticoid receptor (GR), the mineralocorticoid receptor (MR), the 5-hydroxytryptamine-transporter-linked polymorphic region (5-HTTLPR) in the serotonin transporter (5-HTT) and the brain-derived neurotrophic factor (BDNF) gene. Two hundred thirty-two healthy participants were genotyped. The influence of genetic factors on physiological parameters, such as post-awakening cortisol and blood pressure was assessed, as well as the influence of genetic factors on stress reactivity in response to a socially evaluated cold pressor test (SeCPT). Three studies tested the HPA-related genes each on three different levels. The first study examined the influences of genotypes and haplotypes of these five genes on physiological as well as psychological stress indicators (Chapter 2). The second study examined the effects of GR variants (genotypes and haplotypes) and promoter methylation level on both the SAM system and the HPA axis stress reactivity (Chapter 3). The third study comprised the characterization of CRH promoter haplotypes in an in-vitro study and the association of the CRH promoter with stress indicators in vivo (Chapter 4).
In order to investigate the psychobiological consequences of acute stress under laboratory conditions, a wide range of methods for socially evaluative stress induction have been developed. The present dissertation is concerned with evaluating a virtual reality (VR)-based adaptation of one of the most widely used of those methods, the Trier Social Stress Test (TSST). In the three empirical studies collected in this dissertation, we aimed to examine the efficacy and possible areas of application of the adaptation of this well-established psychosocial stressor in a virtual environment. We found that the TSST-VR reliably incites the activation of the major stress effector systems in the human body, albeit in a slightly less pronounced way than the original paradigm. Moreover, the experience of presence is discussed as one potential factor of influence in the origin of the psychophysiological stress response. Lastly, we present a use scenario for the TSST-VR in which we employed the method to investigate the effects of acute stress on emotion recognition performance. We conclude that, due to its advantages concerning versatility, standardization and economic administration, the paradigm harbors enormous potential not only for psychobiological research, but other applications such as clinical practice as well. Future studies should further explore the underlying effect mechanisms of stress in the virtual realm and the implementation of VR-based paradigms in different fields of application.
Entrepreneurship has become an essential phenomenon all over the world because it is a major driving force behind the economic growth and development of a country. It is widely accepted that entrepreneurship development in a country creates new jobs, pro-motes healthy competition through innovation, and benefits the social well being of individuals and societies. The policymakers in both developed and developing countries focus on entrepreneurship because it helps to alleviate impediments to economic development and social welfare. Therefore, policymakers and academic researchers consider the promotion of entrepreneurship as essential for the economy and research-based support is needed for further development of entrepreneurship activities.
The impact of entrepreneurial activities on economic and social development also varies from country to country. The effect of entrepreneurial activities on economic and social development also varies from country to country because the level of entrepreneur-ship activities also varies from one region to another or one country to another. To under-stand these variations, policymakers have investigated the determinants of entrepreneur-ship at different levels, such as the individual, industry, and country levels. Moreover, entrepreneurship behavior is influenced by various personal and environmental level factors. However, these personal-level factors cannot be separated from the surrounding environment.
The link between religion and entrepreneurship is well established and can be traced back to Weber (1930). Researchers have analyzed the relationship between religion and entrepreneurship from various perspectives, and the research related to religion and entrepreneurship is diversified and scattered across disciplines. This dissertation tries to explain the link between religion and entrepreneurship, specifically Islamic religion and entrepreneurship. Technically this dissertation comprises three parts. The first part of this dissertation consists of two chapters that discuss the definition and theories of entrepreneurship (Chapter 2) and the theoretical relationship between religion and entrepreneur-ship (Chapter 3).
The second part of this dissertation (Chapter 4) provides an overview of the field with a purpose to gain a better understanding of the field’s current state of knowledge to bridge the different views and perspectives. In order to provide an overview of the field, a systematic literature search leading to a descriptive overview of the field based on 270 articles published in 163 journals Subsequently, bibliometric methods are used to identify thematic clusters, the most influential authors and articles, and how they are connected.
The third part of this dissertation (Chapter 5) empirically evaluates the influence of Islamic values and Islamic religious practices on entrepreneurship intentions within the Islamic community. Using the theory of planned behavior as a theoretical lens, we also take into account that the relationship between religion and entrepreneurial intentions can be mediated by individual’s attitude towards entrepreneurship. A self-administrative questionnaire was used to collect the responses from a sample of 1895 Pakistani university students. A structured equation modeling was adopted to perform a nuanced assessment of the relationship between Islamic values and practices and entrepreneurship intentions and to account for mediating effect of attitude towards entrepreneurship.
The research on religion and entrepreneurship has increased sharply during the last years and is scattered across various academic disciplines and fields. The analysis identifies and characterize the most important publications, journals, and authors in the area and map the analyzed religions and regions. The comprehensive overview of previous studies allows us to identify research gaps and derive avenues for future research in a substantiated way. Moreover, this dissertation helps the research scholars to understand the field in its entirety, identify relevant articles, and to uncover parallels and differences across religions and regions. Besides, the study reveals a lack of empirical research related to specific religions and specific regions. Therefore, scholars can take these regions and religions into consideration when conducting empirical research.
Furthermore, the empirical analysis about the influence of Islamic religious values and Islamic religious practices show that Islamic values served as a guiding principle in shaping people’s attitudes towards entrepreneurship in an Islamic community; they had an indirect influence on entrepreneurship intention through attitude. Similarly, the relationship between Islamic religious practices and the entrepreneurship intentions of students was fully mediated by the attitude towards entrepreneurship. Furthermore, this dissertation contributes to prior research on entrepreneurship in Islamic communities by applying a more fine-grained approach to capture the link between religion and entrepreneurship. Moreover, it contributes to the literature on entrepreneurship intentions by showing that the influence of religion on entrepreneurship intentions is mainly due to religious values and practices, which shape the attitude towards entrepreneurship and thereby influence entrepreneurship intentions in religious communities. The entrepreneur-ship research has put a higher emphasis on assessing the influence of a diverse set of con-textual factors. This dissertation introduces Islamic values and Islamic religious practices as critical contextual factors that shape entrepreneurship in countries that are characterized by the Islamic religion.
This dissertation investigates corporate acquisition decisions that represent important corporate development activities for family and non-family firms. The main research objective of this dissertation is to generate insights into the subjective decision-making behavior of corporate decision-makers from family and non-family firms and their weighting of M&A decision-criteria during the early pre-acquisition target screening and selection process. The main methodology chosen for the investigation of M&A decision-making preferences and the weighting of M&A decision criteria is a choice-based conjoint analysis. The overall sample of this dissertation consists of 304 decision-makers from 264 private and public family and non-family firms from mainly Germany and the DACH-region. In the first empirical part of the dissertation, the relative importance of strategic, organizational and financial M&A decision-criteria for corporate acquirers in acquisition target screening is investigated. In addition, the author uses a cluster analysis to explore whether distinct decision-making patterns exist in acquisition target screening. In the second empirical part, the dissertation explores whether there are differences in investment preferences in acquisition target screening between family and non-family firms and within the group of family firms. With regards to the heterogeneity of family firms, the dissertation generated insights into how family-firm specific characteristics like family management, the generational stage of the firm and non-economic goals such as transgenerational control intention influences the weighting of different M&A decision criteria in acquisition target screening. The dissertation contributes to strategic management research, in specific to M&A literature, and to family business research. The results of this dissertation generate insights into the weighting of M&A decision-making criteria and facilitate a better understanding of corporate M&A decisions in family and non-family firms. The findings show that decision-making preferences (hence the weighting of M&A decision criteria) are influenced by characteristics of the individual decision-maker, the firm and the environment in which the firm operates.
Auf der Grundlage einer Fragebogenstudie wurden unterschiedliche Elemente eines förderlichen Umgangs mit Gesundheitsinformationen betrachtet und ihre Zusammenhänge mit personspezifischen Merkmalen analysiert. Als zentrale Aspekte der Informationsprozesse wurden die drei Elemente Gesundheitsinformationskompetenz, Gesundheitsinteresse und gesundheitsspezifische Informationsgewohnheiten konzeptuell voneinander getrennt. Auf der Basis des bisherigen Forschungsstands wurde zunächst ein theoretisches Modell des Umgangs mit Gesundheitsinformationen entwickelt, das die Bedeutung der Kompetenz und des Interesses für gesundheitsbezogene Informationsgewohnheiten hervorhebt, individuelle Ausprägungen dieser drei Elemente mit soziodemografischen Faktoren, Persönlichkeitseigenschaften, Überzeugungen und dem Gesundheitszustand in Beziehung setzt sowie Verbindungen zu gesundheitsrelevanten Verhaltensweisen beschreibt. Dieses Modell wurde anschließend an einer Stichprobe von 352 Berufsschülerinnen und -schülern aus drei Berufsbereichen (Wirtschaft/Verwaltung, Technik und Gesundheit) empirisch überprüft. Über multiple Regressionsanalysen wurden bedeutsame Prädiktoren für die drei Hauptelemente Kompetenz, Interesse und Informationsgewohnheiten identifiziert, über logistische Regressionen und Korrelationen ihre Zusammenhänge mit dem Gesundheitsverhalten überprüft. Darüber hinaus wurden lineare Strukturgleichungsmodelle zur Vorhersage des Informationsverhaltens entwickelt. Die Ergebnisse bestätigen die konzeptionelle Trennung der drei Faktoren, die jeweils mit unterschiedlichen Prädiktoren verbunden waren. Auf der Basis der Befunde werden Ansatzpunkte für die weitere Forschung und die Förderung eines kompetenten Umgangs mit Gesundheitsinformationen diskutiert.
Der Photograph Willi Huttig
(2019)
Understanding the mechanisms that shape access to the fisheries ecosystem service in Tsokomey, Accra
(2019)
Questions of access to ecosystem services remain largely unaddressed. Yet, in the coming decades, addressing access to services and securing them for livelihoods and well-being of people will likely gain importance, especially to guide according policies at the local scale. Through a qualitative approach, this paper addresses the mechanisms that shape access to the fisheries eco- system service in Accra, Ghana. The analysis uses a framework that focuses on access to land, tools and technology, knowledge and information, capital and credit, as well as labor. This research reveals how access is organized across the different categories of this framework and how people’s well-being is shaped. Moreover, it helps to further our understanding of what regulates the access to ecosystem services and how to address future shocks and capacity in terms of production of ecosystem services.
In der kleinen ostfriesischen Kirchengemeinde W. hat sich im Jahr 1969 ein plötzlicher Todesfall ereignet. Fremdverschulden wird ausgeschlossen. Jemand, der die Hintergründe des Todesfalls aufklären will, stößt allenthalben auf – bisweilen gar aggressives – Schweigen. Eine Geschichte über individuelle und kollektive Schuld, lutherische Kirchenmusik und den Wert, den wir der Kultur und der Tradition beimessen.
Ausgezeichnet mit dem Borsla-Preis 2019.
For grape canopy pixels captured by an unmanned aerial vehicle (UAV) tilt-mounted RedEdge-M multispectral sensor in a sloped vineyard, an in situ Walthall model can be established with purely image-based methods. This was derived from RedEdge-M directional reflectance and a vineyard 3D surface model generated from the same imagery. The model was used to correct the angular effects in the reflectance images to form normalized difference vegetation index (NDVI)orthomosaics of different view angles. The results showed that the effect could be corrected to a certain scope, but not completely. There are three drawbacks that might restrict a successful angular model construction and correction: (1) the observable micro shadow variation on the canopy enabled by the high resolution; (2) the complexity of vine canopies that causes an inconsistency between reflectance and canopy geometry, including effects such as micro shadows and near-infrared (NIR) additive effects; and (3) the resolution limit of a 3D model to represent the accurate real-world optical geometry. The conclusion is that grape canopies might be too inhomogeneous for the tested method to perform the angular correction in high quality.
In order to discuss potential sustainability issues of expanding silage maize cultivation in Rhineland-Palatinate, spatially explicit monitoring is necessary. Publicly available statistical records are often not a sufficient basis for extensive research, especially on soil health, where risk factors like erosion and compaction depend on variables that are specific to every site, and hard to generalize for larger administrative aggregates. The focus of this study is to apply established classification algorithms to estimate maize abundance for each independent pixel, while at the same time accounting for their spatial relationship. Therefore, two ways to incorporate spatial autocorrelation of neighboring pixels are combined with three different classification models. The performance of each of these modeling approaches is analyzed and discussed. Finally, one prediction approach is applied to the imagery, and the overall predicted acreage is compared to publicly available data. We were able to show that Support Vector Machine (SVM) classification and Random Forests (RF) were able to distinguish maize pixels reliably, with kappa values well above 0.9 in most cases. The Generalized Linear Model (GLM) performed substantially worse. Furthermore, Regression Kriging (RK) as an approach to integrate spatial autocorrelation into the prediction model is not suitable in use cases with millions of sparsely clustered training pixels. Gaussian Blur is able to improve predictions slightly in these cases, but it is possible that this is only because it smoothes out impurities of the reference data. The overall prediction with RF classification combined with Gaussian Blur performed well, with out of bag error rates of 0.5% in 2009 and 1.3% in 2016. Despite the low error rates, there is a discrepancy between the predicted acreage and the official records, which is 20% in 2009 and 27% in 2016.
The forward testing effect refers to the finding that retrieval practice of previously studied information enhances learning and retention of subsequently studied other information. While most of the previous research on the forward testing effect examined group differences, the present study took an individual differences approach to investigate this effect. Experiment 1 examined whether the forward effect has test-retest reliability between two experimental sessions. Experiment 2 investigated whether the effect is related to participants’ working memory capacity. In both experiments (and each session of Experiment 1), participants studied three lists of items in anticipation of a final cumulative recall test. In the testing condition, participants were tested immediately on lists 1 and 2, whereas in the restudy condition, they restudied lists 1 and 2. In both conditions, participants were tested immediately on list 3. On the group level, the results of both experiments demonstrated a forward testing effect, with interim testing of lists 1 and 2 enhancing immediate recall of list 3. On the individual level, the results of Experiment 1 showed that the forward effect on list 3 recall has moderate test-retest reliability between two experimental sessions. In addition, the results of Experiment 2 showed that the forward effect on list 3 recall does not depend on participants’ working memory capacity. These findings suggest that the forward testing effect is reliable at the individual level and affects learners at a wide range of working memory capacities alike. The theoretical and practical implications of the findings are discussed.
This dissertation deals with consistent estimates in household surveys. Household surveys are often drawn via cluster sampling, with households sampled at the first stage and persons selected at the second stage. The collected data provide information for estimation at both the person and the household level. However, consistent estimates are desirable in the sense that the estimated household-level totals should coincide with the estimated totals obtained at the person-level. Current practice in statistical offices is to use integrated weighting. In this approach consistent estimates are guaranteed by equal weights for all persons within a household and the household itself. However, due to the forced equality of weights, the individual patterns of persons are lost and the heterogeneity within households is not taken into account. In order to avoid the negative consequences of integrated weighting, we propose alternative weighting methods in the first part of this dissertation that ensure both consistent estimates and individual person weights within a household. The underlying idea is to limit the consistency conditions to variables that emerge in both the personal and household data sets. These common variables are included in the person- and household-level estimator as additional auxiliary variables. This achieves consistency more directly and only for the relevant variables, rather than indirectly by forcing equal weights on all persons within a household. Further decisive advantages of the proposed alternative weighting methods are that original individual rather than the constructed aggregated auxiliaries are utilized and that the variable selection process is more flexible because different auxiliary variables can be incorporated in the person-level estimator than in the household-level estimator.
In the second part of this dissertation, the variances of a person-level GREG estimator and an integrated estimator are compared in order to quantify the effects of the consistency requirements in the integrated weighting approach. One of the challenges is that the estimators to be compared are of different dimensions. The proposed solution is to decompose the variance of the integrated estimator into the variance of a reduced GREG estimator, whose underlying model is of the same dimensions as the person-level GREG estimator, and add a constructed term that captures the effects disregarded by the reduced model. Subsequently, further fields of application for the derived decomposition are proposed such as the variable selection process in the field of econometrics or survey statistics.
Mit diesem Territorial Science Echo werden wesentliche Facetten von Governance beleuchtet, die sich für die künftige Entwicklung der Großregion als relevant erweisen können. Es wird insbesondere dargestellt, wie thematische Kooperationen und Konflikte zur der Etablierung von Governance Strukturen beitragen. Das Paper setzt sich mit den Themen Governance im Allgemeinen, Partizipation und Wohnen sowie den Außenbeziehungen der Großregion auseinander, formuliert wesentliche Herausforderungen und Empfehlungen, und ist somit als Anregung im fachlichen Diskurs um die weitere Gestaltung des Raumentwicklungskonzeptes der Großregion zu verstehen.
Der vorliegende Sammelband geht auf die UniGR-Fachtagung Edu.GR - Europa leben lernen / Edu.GR - Apprendre à vivre l’Europe zurück, die am 20. September 2018 an der Universität Trier stattfand. Die Beiträge befassen sich aus unterschiedlichen Perspektiven – so aus Sicht der Bildungswissenschaften, der Fachdidaktiken, der Sozialwissenschaften und der Bildungspraxis – mit der Frage der Gestaltung Europas am Beispiel der Großregion. Vorgestellt und diskutiert werden neben Konzepten transnationaler Bildung auch empirische Analysen des Denkens und Handelns der Beteiligten in grenzregionalen (Aus-)Bildungskontexten sowie ausgewählte Beispiele transnationaler Bildungspraxis.
Thema dieser Dissertation ist das deutsche Selbstbildnis im 17. Jahrhundert. Ziel der Arbeit war es, das deutsche Selbstbildnis als eigene Gattung zu etablieren. Hierzu wurden die Selbstbildnisse deutscher Maler des 17. Jahrhunderts ausgewählt, gilt doch diese Zeit noch immer als ‚totes Jahrhundert‘. Grundlage der Untersuchung war eine Sammlung von 148 Objekten, die einer grundlegenden Analyse unterzogen wurden. Das früheste Selbstbildnis in dieser Sammlung stammt von 1600, das späteste wurde um 1700 angefertigt. Künstler aus dem gesamten Alten Reich, ob aus Schlesien und Böhmen, Nord-oder Süddeutschland oder aus den österreichischen wie schweizerischen Landen sind hier vertreten. Die Selbstbildnisse stammen von Malern in der gesamten breite ihrer Karriere. So sind gleichermaßen Selbstbildnisse von Gesellen wie Meistern, von Hofmalern bis hin zu Freimeistern vertreten. Besonders wichtig war es, nicht nur Selbstbildnisse im Gemälde oder Kupferstich in die Untersuchung aufzunehmen, sondern auch Stammbucheinträge.
Die ausführliche Betrachtung und Gegenüberstellung der deutschen Selbstbildnisse mit denen ihrer europäischen Kollegen hat gezeigt, dass auch deutsche Maler den gängigen Darstellungstypen wie etwa dem virtuoso folgten. Aber die deutschen Maler imitierten nicht nur, sondern experimentierten und gingen mit ihren Vorbildern spielerisch um. Daneben folgten sie natürlich auch den Trends der Selbstinszenierung. Sie drückten in ihren Selbstbildnissen ihren Wunsch nach sozialer und gesellschaftlicher Emanzipation des gesamten Berufsstandes aus. So war das deutsche Selbstbildnis eigenständiger Ausdruck des Aufbruches deutscher Künstler in eine neue Zeit.
Competitive analysis is a well known method for analyzing online algorithms.
Two online optimization problems, the scheduling problems and the list accessing problems, are considered in the thesis of Yida Zhu in the respect of this method.
For both problems, several existing online and offline algorithms are studied. Their performances are compared with the performances of corresponding offline optimal algorithms.
In particular, the list accessing algorithm BIT is carefully reviewed.
The classical proof of its worst case performance get simplified by adapting the knowledge about the optimal offline algorithm.
With regard to average case analysis, a new closed formula is developed to determine the performance of BIT on specific class of instances.
All algorithm considered in this thesis are also implemented in Julia.
Their empirical performances are studied and compared with each other directly.
This doctoral thesis includes five studies that deal with the topics work, well-being, and family formation, as well as their interaction. The studies aim to find answers to the following questions: Do workers’ personality traits determine whether they sort into jobs with performance appraisals? Does job insecurity result in lower quality and quantity of sleep? Do public smoking bans affect subjective well-being by changing individuals’ use of leisure time? Can risk preferences help to explain non-traditional family forms? And finally, are differences in out-of-partnership birth rates between East and West Germany driven by cultural characteristics that have evolved in the two separate politico-economic systems? To answer these questions, the following chapters use basic economic subjects such as working conditions, income, and time use, but also employ a range of sociological and psychological concepts such as personality traits and satisfaction measures. Furthermore, all five studies use data from the German Socio-Economic Panel (SOEP), a representative longitudinal panel of private households in Germany, and apply state-of-the-art microeconometric methods. The findings of this doctoral thesis are important for individuals, employers, and policymakers. Workers and employers benefit from knowing the determinants of occupational sorting, as vacancies can be filled more accurately. Moreover, knowing which job-related problems lead to lower well-being and potentially higher sickness absence likely increases efficiency in the workplace. The research on smoking bans and family formation in chapters 4, 5, and 6 is particularly interesting for policymakers. The results on the effects of smoking bans on subjective well-being presented in chapter 4 suggest that the impacts of tobacco control policies could be weighed more carefully. Additionally, understanding why women are willing to take the risks associated with single motherhood can help to improve policies targeting single mothers.
Die publikationsbasierte Dissertation untersucht die Bedeutung sozialer Bewegungen für die Entwicklung der Sozialen Arbeit am Ende des 19. und den ersten Jahrzehnten des 20. Jahrhunderts als Profession und Disziplin in den USA und in Deutschland. Dabei wird die entstehende Soziale Arbeit als ‚Formbildung‘ sozialer Bewegungen verstanden und gefragt, wie sich die Bewegungen in die sich etablierende und institutionalisierende Profession und Wissenschaft Soziale Arbeit einschreiben, welche Anliegen dabei verfolgt werden und wie dadurch Wissen in der Sozialen Arbeit auch über nationalstaatliche Grenzen hinweg zirkuliert.
Die Untersuchung konzentriert sich auf Prozesse der Pädagogisierung, also unterschiedliche ‚Formbildungen des Pädagogischen‘, die die Bewegungsanliegen zum Thema von Aufklärung, (Selbst)Bildung und Pädagogik machen, und auf solche der Verwissenschaftlichung, die sich auf den Aufbau einer Wissensgrundlage zur Bearbeitung von sozialen Problemen richten und dabei alternative Formen der Wissensproduktion ausbilden. Diese Prozesse werden in drei Teilstudien – zur Charity Organization Movement und der Settlement House Movement in den USA sowie der bürgerlichen Frauenbewegung in Deutschland – in sieben Einzelbeiträgen näher untersucht. Im Mittelpunkt stehen dabei die Handlungsmethoden und das Praxisverständnis sowie Forschungskonzepte und –projekte exemplarisch ausgewählter sozialbewegter Initiativen der Sozialen Arbeit. Dabei werden unter anderem nicht-intendierte Effekte untersucht, die zum Beispiel in Konservierungen normativer Vorstellungen und Ideologien in als demokratisierend angelegten Ansätzen, aber auch in ‚differenzverstärkenden‘ Effekten bestehen können.
La participation des élèves ne devrait pas se limiter à l’implication dans l’organisation et l’évaluation des cours. Une culture de tâches participative offre de nombreuses possibilités pour pratiquer et analyser la participation démocratique à l’aide d’actions réelles ou simulées dans l’apprentissage technique.
Considérer les processus d’évaluation à l’école comme une possibilité pour soutenir les élèves dans l’évaluation réaliste et le développement de leurs processus et leur comportement d’apprentissage : l’évaluation participative des performances offre différentes possibilités pratiques pour favoriser la motivation d’apprendre, l’autoréflexion et la compréhension démocratique.
Le feedback à l’école ? Il s’agit souvent d’un simple retour d’informations des enseignant(e)s sur le travail des élèves en classe. Cependant, une culture du feedback solide en classe offre de nombreuses possibilités pour pratiquer l’action démocratique et améliorer la qualité de l’enseignement, tout en faisant participer enseignant(e)s et apprenant(e)s.
Les carnets paraissent deux fois par an et offrent aux dirigeant(e)s des écoles ainsi qu’au personnel des fondements théoriques et du matériel pratique pour la mise en oeuvre d’un développement scolaire démocratique. Chaque publication traite d’une méthode de l’éducation à la démocratie ou d’une question stratégique du développement scolaire. Les carnets en langue allemande sont mis à la disposition des écoles luxembourgeoises en version imprimée. Tout le matériel ainsi que la version en langue française sont disponibles en ligne.
Participer à l’enseignement dès le plus jeune âge – est-ce possible ? Les discussions et les processus de négociation et de décision ne nécessitent-ils pas une certaine maturité dont les enfants de trois ans ne disposent pas encore ? L’équipe mateneen s’est fait une idée du travail avec des enfants préscolaires et a constaté : que c’était tout à fait possible !
L’enseignement participatif, qui ne se résume pas à une participation vécue ponctuellement, comme l’écrit Charlotte Keuler dans l’article principal de ce carnet, est devenu indispensable à plusieurs égards en raison des défis auxquels nous confronte notre monde globalisé. La capacité à communiquer, les compétences interculturelles, la gestion des connaissances et d’autres « soft skills » sont les compétences clés du 21e siècle.
L’enseignement participatif
(2019)
L‘école est un lieu de socialisation des enfants et des jeunes. Les heures de cours de l‘enseignement des différentes matières sont un espace d‘expérimentation de cette socialisation. Elles marquent par leur durée dans la journée aussi bien le rôle fondamental de l‘école que l‘action et la perception à la fois des enseignant(e)s et des apprenant(e)s. Il apparaît donc d’autant plus important d’intégrer ces cours dans l’organisation d’une culture scolaire démocratique.
This thesis discusses revue as a significantly inter-cultural genre in the history of global theatre. During the ‘modernisation’ period in Europe, America and Japan, most major urban cities experienced a boom in revue venues and performances. Few studies about revue have yet been done in theatre studies or in urban cultural studies. My thesis will attempt to reevaluate and redefine revue as a highly intercultural theatre genre by using the concept of liminality. In other words, the aim is to examine revue as a genre built on ‘modern composition of betweenness’, bridging seemingly opposing elements, such as the foreign and the domestic, the classic and the innovative, the traditional and the modern, the professional and the amateur, high and low culture, and the feminine and the masculine. The goal is to regard revue as a liminal genre constructed amidst the negotiations between these binaries, existing in a state of constant flux.
The purpose of this approach is to capture revue as a transitory phenomena in five dimensions: conceptual, spatial, temporal, categorical and physical. Over the course of six chapters, this
inter-disciplinary discussion will reveal the reasons why and the ways by which revue came to establish its prominent position in the Japanese theatre industry. The whole structure is also an attempt to provide plausible ways to apply sociological considerations to theatre studies.
Finding behavioral parameterization for a 1-D water balance model by multi-criteria evaluation
(2019)
Evapotranspiration is often estimated by numerical simulation. However, to produce accurate simulations, these models usually require on-site measurements for parameterization or calibration. We have to make sure that the model realistically reproduces both, the temporal patterns of soil moisture and evapotranspiration. In this study, we combine three sources of information: (i) measurements of sap velocities; (ii) soil moisture; and (iii) expert knowledge on local runoff generation and water balance to define constraints for a “behavioral” forest stand water balance model. Aiming for a behavioral model, we adjusted soil moisture at saturation, bulk resistance parameters and the parameters of the water retention curve (WRC). We found that the shape of the WRC influences substantially the behavior of the simulation model. Here, only one model realization could be referred to as “behavioral”. All other realizations failed for a least one of our evaluation criteria: Not only transpiration and soil moisture are simulated consistently with our observations, but also total water balance and runoff generation processes. The introduction of a multi-criteria evaluation scheme for the detection of unrealistic outputs made it possible to identify a well performing parameter set. Our findings indicate that measurement of different fluxes and state variables instead of just one and expert knowledge concerning runoff generation facilitate the parameterization of a hydrological model.
Nonlocal operators are used in a wide variety of models and applications due to many natural phenomena being driven by nonlocal dynamics. Nonlocal operators are integral operators allowing for interactions between two distinct points in space. The nonlocal models investigated in this thesis involve kernels that are assumed to have a finite range of nonlocal interactions. Kernels of this type are used in nonlocal elasticity and convection-diffusion models as well as finance and image analysis. Also within the mathematical theory they arouse great interest, as they are asymptotically related to fractional and classical differential equations.
The results in this thesis can be grouped according to the following three aspects: modeling and analysis, discretization and optimization.
Mathematical models demonstrate their true usefulness when put into numerical practice. For computational purposes, it is important that the support of the kernel is clearly determined. Therefore nonlocal interactions are typically assumed to occur within an Euclidean ball of finite radius. In this thesis we consider more general interaction sets including norm induced balls as special cases and extend established results about well-posedness and asymptotic limits.
The discretization of integral equations is a challenging endeavor. Especially kernels which are truncated by Euclidean balls require carefully designed quadrature rules for the implementation of efficient finite element codes. In this thesis we investigate the computational benefits of polyhedral interaction sets as well as geometrically approximated interaction sets. In addition to that we outline the computational advantages of sufficiently structured problem settings.
Shape optimization methods have been proven useful for identifying interfaces in models governed by partial differential equations. Here we consider a class of shape optimization problems constrained by nonlocal equations which involve interface-dependent kernels. We derive the shape derivative associated to the nonlocal system model and solve the problem by established numerical techniques.
In this thesis, we aim to study the sampling allocation problem of survey statistics under uncertainty. We know that the stratum specific variances are generally not known precisely and we have no information about the distribution of uncertainty. The cost of interviewing each person in a stratum is also a highly uncertain parameter as sometimes people are unavailable for the interview. We propose robust allocations to deal with the uncertainty in both stratum specific variances and costs. However, in real life situations, we can face such cases when only one of the variances or costs is uncertain. So we propose three different robust formulations representing these different cases. To the best of our knowledge robust allocation in the sampling allocation problem has not been considered so far in any research.
The first robust formulation for linear problems was proposed by Soyster (1973). Bertsimas and Sim (2004) proposed a less conservative robust formulation for linear problems. We study these formulations and extend them for the nonlinear sampling allocation problem. It is very unlikely to happen that all of the stratum specific variances and costs are uncertain. So the robust formulations are in such a way that we can select how many strata are uncertain which we refer to as the level of uncertainty. We prove that an upper bound on the probability of violation of the nonlinear constraints can be calculated before solving the robust optimization problem. We consider various kinds of datasets and compute robust allocations. We perform multiple experiments to check the quality of the robust allocations and compare them with the existing allocation techniques.
Partizipation im Unterricht von klein auf – geht das? Braucht man für Diskussionen, Aushandlungs-und Entscheidungsprozesse nicht eine bestimmte Reife, über die Dreijährige noch gar nicht verfügen? Das mateneen-Team hat sich auf Limpertsberg ein Bild von der Arbeit mit Vorschulkindern gemacht und festgestellt: das geht sehr wohl!
Partizipativer Unterricht, der nicht nur aus punktuell erlebter Teilnahme besteht, ist — wie Charlotte Keuler es im Leitartikel des vorliegenden Heftes formuliert — durch die Herausforderungen, vor die uns unsere globalisierte Welt stellt, in vielerlei Hinsicht unabdingbar geworden. Kommunikationsfähigkeit, interkulturelle Kompetenz, Wissensmanagement und andere oft zitierte „soft skills“ sind Schlüsselkompetenzen des 21. Jahrhunderts.
Fachunterricht ist der zentrale Erfahrungsraum im Sozialisationsumfeld Schule. Er prägt schon allein aufgrund seines hohen zeitlichen Anteils im Tagesverlauf und der grundlegenden Funktion von Schule Handeln und Wahrnehmung von Lehrpersonen und Lernenden. Umso wichtiger ist es, ihn in die Gestaltung einer demokratischen Schulkultur einzubeziehen.
Bewertungsprozesse in der Schule als Möglichkeit nutzen, um Schüler*innen bei der realistischen Einschätzung und Weiterentwicklung ihrer Lernprozesse und ihres Lernverhaltens zu unterstützen: Die partizipative Leistungsbewertung bietet verschiedene praxisnahe Ansätze zur Förderung von Lernmotivation, Selbstreflexion und demokratischem Verständnis.